We've not really been using the Focal containerfile, as we move
forward jammy is a better choice for keeping stable as we might find
some new users for it.
Also add binutils to bindep for native bullseye builds (see
Icb0e40827c9f8ac583fa143545e6bed9641bf613)
Change-Id: I22ebe2bbccaec34180e58996b21e47bfc4f36055
This is a base element which uses a containerfile (Dockerfile) to
build a container image, then the filesystem is extracted from that
image and forms the root of the dib image.
You can add as little or as much to the dockerfile as desired.
Change-Id: I4e821aa2ce7feb8841ef31da56de1a31aa9218b5